Mitochondrial genotype of a unisexual salamander of hybrid origin is unrelated to either of its nuclear haplotypes.

Abstract

We examined mitochondrial DNA (mtDNA), enzyme, and morphological variation among 17 unisexual Ambystoma of hybrid origin. Electrophoretic comparison of diagnostic enzymes indicates that these unisexuals are triploid with two nuclear genomes from the bisexual species Ambystoma laterale and one from Ambystoma jeffersonianum; however, according to restriction analysis, the mtDNAs of these specimens derive from a third species, Ambystoma texanum. This unusual situation is apparently due to a partially independent segregation event in an ancestor of these unisexuals. This situation highlights the potential importance of molecules with different inheritance patterns in elucidating complex cases of reticulate evolution.